/*
 * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.
 * Copyright (c) 2006-2018 Christian Walter <cwalter@embedded-solutions.at>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * File: $Id: mbfunccoils.c,v 1.8 2007/02/18 23:47:16 wolti Exp $
 */

/* ----------------------- System includes ----------------------------------*/
#include "stdlib.h"
#include "string.h"

/* ----------------------- Platform includes --------------------------------*/
#include "port.h"

/* ----------------------- Modbus includes ----------------------------------*/
#include "mb.h"
#include "mbframe.h"
#include "mbproto.h"
#include "mbconfig.h"

/* ----------------------- Defines ------------------------------------------*/
#define MB_PDU_FUNC_READ_ADDR_OFF           ( MB_PDU_DATA_OFF )
#define MB_PDU_FUNC_READ_COILCNT_OFF        ( MB_PDU_DATA_OFF + 2 )
#define MB_PDU_FUNC_READ_SIZE               ( 4 )
#define MB_PDU_FUNC_READ_COILCNT_MAX        ( 0x07D0 )

#define MB_PDU_FUNC_WRITE_ADDR_OFF          ( MB_PDU_DATA_OFF )
#define MB_PDU_FUNC_WRITE_VALUE_OFF         ( MB_PDU_DATA_OFF + 2 )
#define MB_PDU_FUNC_WRITE_SIZE              ( 4 )

#define MB_PDU_FUNC_WRITE_MUL_ADDR_OFF      ( MB_PDU_DATA_OFF )
#define MB_PDU_FUNC_WRITE_MUL_COILCNT_OFF   ( MB_PDU_DATA_OFF + 2 )
#define MB_PDU_FUNC_WRITE_MUL_BYTECNT_OFF   ( MB_PDU_DATA_OFF + 4 )
#define MB_PDU_FUNC_WRITE_MUL_VALUES_OFF    ( MB_PDU_DATA_OFF + 5 )
#define MB_PDU_FUNC_WRITE_MUL_SIZE_MIN      ( 5 )
#define MB_PDU_FUNC_WRITE_MUL_COILCNT_MAX   ( 0x07B0 )

/* ----------------------- Static functions ---------------------------------*/
eMBException prveMBError2Exception(eMBErrorCode eErrorCode);

/* ----------------------- Start implementation -----------------------------*/

#if MB_FUNC_READ_COILS_ENABLED > 0

eMBException eMBFuncReadCoils(UCHAR *pucFrame, USHORT *usLen) {
	USHORT usRegAddress;
	USHORT usCoilCount;
	UCHAR ucNBytes;
	UCHAR *pucFrameCur;

	eMBException eStatus = MB_EX_NONE;
	eMBErrorCode eRegStatus;

	if (*usLen == ( MB_PDU_FUNC_READ_SIZE + MB_PDU_SIZE_MIN)) {
		usRegAddress = (USHORT) (pucFrame[MB_PDU_FUNC_READ_ADDR_OFF] << 8);
		usRegAddress |= (USHORT) (pucFrame[MB_PDU_FUNC_READ_ADDR_OFF + 1]);
		usRegAddress++;

		usCoilCount = (USHORT) (pucFrame[MB_PDU_FUNC_READ_COILCNT_OFF] << 8);
		usCoilCount |= (USHORT) (pucFrame[MB_PDU_FUNC_READ_COILCNT_OFF + 1]);

		/* Check if the number of registers to read is valid. If not
		 * return Modbus illegal data value exception.
		 */
		if ((usCoilCount >= 1)
				&& (usCoilCount < MB_PDU_FUNC_READ_COILCNT_MAX)) {
			/* Set the current PDU data pointer to the beginning. */
			pucFrameCur = &pucFrame[MB_PDU_FUNC_OFF];
			*usLen = MB_PDU_FUNC_OFF;

			/* First byte contains the function code. */
			*pucFrameCur++ = MB_FUNC_READ_COILS;
			*usLen += 1;

			/* Test if the quantity of coils is a multiple of 8. If not last
			 * byte is only partially field with unused coils set to zero. */
			if ((usCoilCount & 0x0007) != 0) {
				ucNBytes = (UCHAR) (usCoilCount / 8 + 1);
			} else {
				ucNBytes = (UCHAR) (usCoilCount / 8);
			}
			*pucFrameCur++ = ucNBytes;
			*usLen += 1;

			eRegStatus = eMBRegCoilsCB(pucFrameCur, usRegAddress, usCoilCount,
					MB_REG_READ);

			/* If an error occured convert it into a Modbus exception. */
			if (eRegStatus != MB_ENOERR) {
				eStatus = prveMBError2Exception(eRegStatus);
			} else {
				/* The response contains the function code, the starting address
				 * and the quantity of registers. We reuse the old values in the
				 * buffer because they are still valid. */
				*usLen += ucNBytes;
				;
			}
		} else {
			eStatus = MB_EX_ILLEGAL_DATA_VALUE;
		}
	} else {
		/* Can't be a valid read coil register request because the length
		 * is incorrect. */
		eStatus = MB_EX_ILLEGAL_DATA_VALUE;
	}
	return eStatus;
}
#endif

#if MB_FUNC_WRITE_COIL_ENABLED > 0
eMBException eMBFuncWriteCoil(UCHAR *pucFrame, USHORT *usLen) {
	USHORT usRegAddress;
	UCHAR ucBuf[2];

	eMBException eStatus = MB_EX_NONE;
	eMBErrorCode eRegStatus;

	if (*usLen == ( MB_PDU_FUNC_WRITE_SIZE + MB_PDU_SIZE_MIN)) {
		usRegAddress = (USHORT) (pucFrame[MB_PDU_FUNC_WRITE_ADDR_OFF] << 8);
		usRegAddress |= (USHORT) (pucFrame[MB_PDU_FUNC_WRITE_ADDR_OFF + 1]);
		usRegAddress++;

		if ((pucFrame[MB_PDU_FUNC_WRITE_VALUE_OFF + 1] == 0x00)
				&& ((pucFrame[MB_PDU_FUNC_WRITE_VALUE_OFF] == 0xFF)
						|| (pucFrame[MB_PDU_FUNC_WRITE_VALUE_OFF] == 0x00))) {
			ucBuf[1] = 0;
			if (pucFrame[MB_PDU_FUNC_WRITE_VALUE_OFF] == 0xFF) {
				ucBuf[0] = 1;
			} else {
				ucBuf[0] = 0;
			}
			eRegStatus = eMBRegCoilsCB(&ucBuf[0], usRegAddress, 1,
					MB_REG_WRITE);

			/* If an error occured convert it into a Modbus exception. */
			if (eRegStatus != MB_ENOERR) {
				eStatus = prveMBError2Exception(eRegStatus);
			}
		} else {
			eStatus = MB_EX_ILLEGAL_DATA_VALUE;
		}
	} else {
		/* Can't be a valid write coil register request because the length
		 * is incorrect. */
		eStatus = MB_EX_ILLEGAL_DATA_VALUE;
	}
	return eStatus;
}

#endif

#if MB_FUNC_WRITE_MULTIPLE_COILS_ENABLED > 0
eMBException eMBFuncWriteMultipleCoils(UCHAR *pucFrame, USHORT *usLen) {
	USHORT usRegAddress;
	USHORT usCoilCnt;
	UCHAR ucByteCount;
	UCHAR ucByteCountVerify;

	eMBException eStatus = MB_EX_NONE;
	eMBErrorCode eRegStatus;

	if (*usLen > ( MB_PDU_FUNC_WRITE_SIZE + MB_PDU_SIZE_MIN)) {
		usRegAddress = (USHORT) (pucFrame[MB_PDU_FUNC_WRITE_MUL_ADDR_OFF] << 8);
		usRegAddress |= (USHORT) (pucFrame[MB_PDU_FUNC_WRITE_MUL_ADDR_OFF + 1]);
		usRegAddress++;

		usCoilCnt = (USHORT) (pucFrame[MB_PDU_FUNC_WRITE_MUL_COILCNT_OFF] << 8);
		usCoilCnt |= (USHORT) (pucFrame[MB_PDU_FUNC_WRITE_MUL_COILCNT_OFF + 1]);

		ucByteCount = pucFrame[MB_PDU_FUNC_WRITE_MUL_BYTECNT_OFF];

		/* Compute the number of expected bytes in the request. */
		if ((usCoilCnt & 0x0007) != 0) {
			ucByteCountVerify = (UCHAR) (usCoilCnt / 8 + 1);
		} else {
			ucByteCountVerify = (UCHAR) (usCoilCnt / 8);
		}

		if ((usCoilCnt >= 1) && (usCoilCnt <= MB_PDU_FUNC_WRITE_MUL_COILCNT_MAX)
				&& (ucByteCountVerify == ucByteCount)) {
			eRegStatus = eMBRegCoilsCB(
					&pucFrame[MB_PDU_FUNC_WRITE_MUL_VALUES_OFF], usRegAddress,
					usCoilCnt, MB_REG_WRITE);

			/* If an error occured convert it into a Modbus exception. */
			if (eRegStatus != MB_ENOERR) {
				eStatus = prveMBError2Exception(eRegStatus);
			} else {
				/* The response contains the function code, the starting address
				 * and the quantity of registers. We reuse the old values in the
				 * buffer because they are still valid. */
				*usLen = MB_PDU_FUNC_WRITE_MUL_BYTECNT_OFF;
			}
		} else {
			eStatus = MB_EX_ILLEGAL_DATA_VALUE;
		}
	} else {
		/* Can't be a valid write coil register request because the length
		 * is incorrect. */
		eStatus = MB_EX_ILLEGAL_DATA_VALUE;
	}
	return eStatus;
}

#endif
